Liquid phase coating to produce controlled-release alginate microspheres

Area of Science:

• Materials Science
• Pharmaceutical Technology
• Polymer Chemistry

Background:

• Alginate microspheres are widely used in drug delivery.
• Developing effective coating techniques for microspheres is crucial for controlled release.
• Polymethyl methacrylate (PMMA) offers tunable properties for drug encapsulation.

Purpose of the Study:

• To explore a liquid phase coating technique for producing PMMA-coated alginate microspheres.
• To investigate the drug release characteristics of these coated microspheres in simulated gastric and intestinal fluids.
• To evaluate the influence of drug load and core:coat ratio on encapsulation efficiency and release kinetics.

Main Methods:

• Preparation of alginate microspheres via emulsification.
• Coating of alginate microspheres with different PMMA types using a liquid phase technique.
• In vitro release studies using paracetamol as a model drug in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).
• Analysis of drug release kinetics using Higuchi's square root model.

Main Results:

• PMMA-coated alginate microspheres demonstrated significantly retarded drug release in SGF and SIF.
• Eudragit RS100 coatings showed similar release rates in SGF and SIF due to insolubility.
• Eudragit S100 coatings provided sustained release in SGF, with faster release in SIF (pH > 7.0).
• Drug release rate was influenced by the core:coat ratio.
• Higuchi's square root model accurately described the drug release mechanism.

Conclusions:

• The developed liquid phase coating technique is efficient for coating small microspheres.
• This method minimizes drug loss during the coating process.
• The technique facilitates the development of controlled drug release systems using PMMA-coated alginate microspheres.